I have a 06 custom and it too leaked at the seam of the plastic tank. I used "loctite 4471" its a industrial superglue which not only glues but melts plastic. I ran 2-3 seams of it along the seam and it fixed my problem. Not sure for how long, but its held for 2000 miles so far.

 

OK, old thread but I just had my oil tank blow out. It blew the cover off and across the garage about 5 feet. I've ridden in very cold weather but from the description above I'm guessing something froze? Not sure what, this is a stock 2006 Sportster 1200 low with 98,500 miles.
Can anyone explain in lay-man's terms what happened or at least what I should look at replacing besides the tank?
BTW the tank blew at the seam on the outside just under the fill neck.
Thank you

 

drama here:

 

agreed, they dropped the ball all over this lil scooter. its has become a pain in my neck , my back! Owe! (sisters bike)